1. Field of the Invention
The present invention relates to a master management server, a cache management server, and a print document information management system.
2. Description of the Related Art
Print document information management systems that manage document data to be printed and printers for printing such data are conventionally known. A print document information management system receives document data from a user application or from another document management system, generates print document information, and associates the print document information with the document data before storing the print document information. In response to a user request for a list of print documents, the print document information management system returns a list of print document information, and displays the list on the user's terminal. According to a user request for printing, the print document information management system performs printing processing, and reflects the progress and result of the printing processing in the print document information.
Print document information management systems can set access rights for print documents that the print document information management systems manage. When a print document information management system receives a user request for a list of print documents, the print document information management system identifies the user who made the request, and returns information only on the print documents to which the user has been granted access. In response to a user request for printing, the print document information management system also allows or denies the request according to the setting of an access right.
Furthermore, a print document information management system can set storage expiration dates and printable expiration dates for respective print documents. For print documents whose printable expiration date has passed, the print document information management system sets a non-printable status and denies user requests to print those documents. The print document information management system deletes print documents whose storage expiration date has passed from the print document information management system. The term “disposal processing on print documents”, as used herein, means processing in which a print document information management system finds print documents whose storage expiration date or printable expiration date has passed and processes those documents once a day.
A print document information management system usually manages information on print documents in a database, and searches the database to generate a list of print documents to be returned to a user. The information on print documents stored in the database is frequently updated because the information on print documents reflects the progress and result of printing processing in real time. Thus, print document information management systems are provided with master databases used for updating purposes and cache databases used for reference purposes. Each time information in the master databases is updated, the print document information management system asynchronously notifies the cache databases of the update information, so that the master databases reflect the update information. The cache databases are not necessarily in a one-to-one correspondence with the master databases, and the databases do not necessarily have the same structure. For example, multiple cache databases may be provided for each master database to achieve load distribution. This enables the number of users who can make reference to increase. Cache databases may also be built with consideration given to lists of print documents returned to users. For example, when users belong to multiple groups, and print documents of the users belonging to each group are desired to be referenced, the cache databases may be built so that the print documents of the users belonging to each group are collected in advance.
In recent years, the penetration of the Internet and the emergence of high-speed networks have allowed an increasing number of functions that were used to be provided as software to be offered as services on the Internet. As the back-end of such services, a print document information management system may serve. In that case, the print document information management system is required to manage an incomparably larger amount of print documents than ever before. In the print document information management system managing such a large amount of print documents, tens of thousands of master databases and cache databases manage the print documents in a distributed manner. When the print document information management system performs disposal processing, an enormous amount of information on print documents is updated, resulting in generation of a large volume of update information of which the cache databases are to be notified. This puts the entire print document information management system under heavy load. For example, assume a case in which each master database performs disposal processing on 100,000 print documents. In this case, update information for the product of 100,000 print documents and the number of master databases flows through the network. In a system configuration that includes multiple cache databases for each master database, the amount of update information flowing through the network can be still many times larger.
To address this problem, Japanese Patent Application Laid-Open No. 2002-007441 describes a system in which a deletion table and an addition table are generated. When a master database is updated, deleted records are registered in the deletion table, and added records are registered in the addition table. These are sent as compressed files to a location where cache databases are managed.
However, in the method described in Japanese Patent Application Laid-Open No. 2002-007441, after updating of the master database is completed, all pieces of update information are simultaneously transmitted to the location where the cache databases are managed. Then, updating of the cache databases is started. Thus, in processing, such as disposal processing, in which a large volume of information is updated at a time, it takes a long time to reach the completion of the updating of the cache databases. For example, when execution of disposal is supposed to be accomplished by batch processing performed during nighttime hours, the disposal processing on the entire system may not be completed by the next morning, causing inconvenience to the conduct of the business on the next day.